server {
    listen 80;
    server_name localhost;
    root /usr/share/nginx/html;
    index index.html;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_types text/plain text/css text/xml text/javascript application/javascript application/json application/xml;

    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;

    # Cache static assets
    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    # Service worker - no cache
    location /sw.js {
        expires off;
        add_header Cache-Control "no-cache, no-store, must-revalidate";
    }

    # PWA manifest
    location /manifest.webmanifest {
        types { application/manifest+json webmanifest; }
    }

    # SPA fallback
    location / {
        try_files $uri $uri/ /index.html;
    }
}